Code No.P1571: Malfunction of the Stop Lamp Switch System.












OPERATION



  • For the stop lamp switch, two switches, a stop lamp switch for the stop lamp illumination and a brake switch exclusively for the cruise control system, are incorporated to improve the reliability.
  • The engine-ECU connector D-215 terminal No.125 and No.126 monitor the state of the stop lamp switch and the brake switch.
  • The stop lamp switch and brake switch turn ON/OFF when the brake pedal is depressed/released, and the input signal to the engine-ECU changes. According to this change, the engine-ECU judges the state of the stop lamp switch and the brake switch.

DIAGNOSIS CODE SET CONDITIONS


Check Condition
  • The cruise control indicator lamp illuminates.
Judgement Criteria
  • Open/short in stop lamp switch circuit.
  • Open circuit in the brake switch circuit (between engine-ECU terminal No.126 and earth.)

PROBABLE CAUSES



  • Damaged harness or connector.
  • Malfunction of the stop lamp switch.
  • Malfunction of the engine-ECU.

DIAGNOSIS PROCEDURE

STEP 1. Check the data list.
Using M.U.T.-III, check the data list (Refer to - data list reference table.)

  • Item 135: Stop lamp switch.

Q. Is the check result normal?
Go to Step 14.
Go to Step 2.

STEP 2. Check the stop lamp operation.
Check the stop lamp operation.
OK:

    Brake pedal depressed: Stop lamp will illuminate.
    Brake pedal not depressed: Stop lamp does not illuminate.

Q. Is the check result normal?
Go to Step 3.
Go to Step 6.

STEP 3. Connectors check: D-215 engine-ECU connector, D-113 J/C (6), and D-230 intermediate connector.

Q. Is the check result normal?
Go to Step 4.
Repair or replace the damaged connector. Then go to Step 20.

STEP 4. Check the harness wire between engine-ECU connector D-215 terminal No.125 and stop lamp switch connector D-134 terminal No.1.

  • Check harness wire for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 5.
Repair the damaged harness wire. Then go to Step 20.

STEP 5. Check the data list.
Using M.U.T.-III, check the data list (Refer to - data list reference table.)

  • Item 135: Stop lamp switch.

Q. Is the check result normal?
Go to Step 14.
Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU .) Then go to Step 20.

STEP 6. Measure the terminal voltage at stop lamp switch connector D-134.
(1)Disconnect stop lamp switch connector D-134 and measure at the harness connector side.
(2)Measure the terminal voltage between stop lamp switch connector D-134 terminal No.2 and earth.
OK: System voltage

Q. Is the check result normal?
Go to Step 10.
Go to Step 7.

STEP 7. Connectors check: D-134 stop lamp switch connector and D-241 intermediate connector.

Q. Is the check result normal?
Go to Step 8.
Repair or replace the damaged connector. Then go to Step 20.

STEP 8. Check the harness wire between stop lamp switch connector D-134 terminal No.2 and fuse No.16 at the relay box in engine compartment.

  • Check harness wire for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 9.
Repair or replace the damaged harness wire. Then go to Step 20.

STEP 9. Check the fuse No.16 at the relay box in engine compartment.

Q. Is the check result normal?
Go to Step 13.
Check the stop lamp system harness and replace the fuse. Then go to Step 20.

STEP 10. Connector check: D-134 stop lamp switch connector.

Q. Is the check result normal?
Go to Step 11.
Repair or replace the damaged connector. Then go to Step 20.

STEP 11. Check the harness wire between stop lamp switch connector D-134 terminal No.1 and intermediate connector D-230 terminal No.10.

  • Check harness wire for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 12.
Repair or replace the damaged harness wire. Then go to Step 20.

STEP 12. Check the stop lamp switch.
Refer to GROUP 35A - Brake Pedal, Inspection, Stop Lamp Switch Check .

Q. Is the check result normal?
Go to Step 13.
Replace the stop lamp switch (Refer to GROUP 35A - Brake Pedal ). Then go to Step 20.

STEP 13. Check the data list.
Using M.U.T.-III, check the data list (Refer to - data list reference table.)

  • Item 135: Stop lamp switch.

Q. Is the check result normal?
Go to Step 14.
Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU .) Then go to Step 20.

STEP 14. Check the data list.
Using M.U.T.-III, check the data list (Refer to - data list reference table.)

  • Item 134: Brake switch.

Q. Is the check result normal?
Go to Step 19.
Go to Step 15.

STEP 15. Connectors check: D-134 stop lamp switch connector, D-231 intermediate connector and D-215 engine-ECU connector.

Q. Is the check result normal?
Go to Step 16.
Repair or replace the damaged connector. Then go to Step 20.

STEP 16. Check the harness wire between engine-ECU connector D-215 terminal No.126 and stop lamp switch connector D-134 terminal No.4, and between stop lamp switch connector D-134 terminal No.3 and earth.

  • Check harness wire for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 17.
Repair the damaged harness wire. Then go to Step 20.

STEP 17. Check the stop lamp switch.
Refer to GROUP 35A - Brake Pedal, Inspection, Stop Lamp Switch Check .

Q. Is the check result normal?
Go to Step 18.
Replace the stop lamp switch (Refer to GROUP 35A - Brake Pedal ). Then go to Step 20.

STEP 18. Check the data list.
Using M.U.T.-III, check the data list (Refer to - data list reference table.)

  • Item 134: Brake switch.

Q. Is the check result normal?
Go to Step 19.
Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU .) Then go to Step 20.

STEP 19. Read the diagnosis code.
(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system (Refer to ).
(2)Turn the ignition switch to the "ON" position, and push the "ON/OFF" switch to turn the cruise control system to ON (turn ON the cruise control indicator lamp).
(3)With the cruise control switches not operated, depress the brake pedal for several seconds, and then use the M.U.T.-III to read the diagnosis code of the cruise control system (Refer to ).

Q. Is diagnosis code No.P1571 set?
Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU .) Then go to Step 20.
It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions .)

STEP 20. Check the data list.
Using M.U.T.-III, check the data list (Refer to - data list reference table.)

  • Item 134: Brake switch.
  • Item 135: Stop lamp switch.

Q. Is the check result normal?
Go to Step 21.
Return to Step 1.

STEP 21. Read the diagnosis code.
(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system (Refer to ).
(2)Turn the ignition switch to the "ON" position, and push the "ON/OFF" switch to turn the cruise control system to ON (turn ON the cruise control indicator lamp).
(3)With the cruise control switches not operated, depress the brake pedal for several seconds, and then use the M.U.T.-III to read the diagnosis code of the cruise control system (Refer to ).

Q. Is diagnosis code No.P1571 set?
Return to Step 1.
The procedure is complete.